The present invention concerns a method for a gas- and fluid-tight sealing of non-threaded boreholes which are under pressure, and are situated in a hardenable raw material, with the aid of a sealing member, especially of a spherical means which is being pressed into a borehole.
It is known in the prior art to utilize steel balls for the purpose of sealing non-threaded boreholes in housings of hydraulic or pneumatic devices. The housings have consisted of a building steel or a gray (cast) iron in most cases, so that when said steel balls were pressed into the boreholes few difficulties developed. In the use of these types of raw materials, the possibility of wedging over the boreholes to some extent at their outer end portions was utilized so that the ball could more positively be prevented from moving outwardly. However, certain difficulties developed when housing comprising hardenable raw materials were used, since the pushing-in of a ball after the hardening process in itself became difficult, and, additionally, there existed the danger of splintering-off or flaking-off the edges of the hardened surfaces. An effort has been made for removing this disadvantage by using the case-hardened steels as work material and by covering certain of the boreholes sections before the insertion. In this way, one obtained soft borehole sections, however, one was forced to accept also the increased costs and expenses for the covering, in addition to the costs for the comparatively expensive case-hardened steels.